I've been having some issues with my 93 and I was hoping you guys would be able to lead me into the right direction.

My car starts up fine and runs fine as well as long as I'm crusing and not mashing the pedal down. But if I give it a little bit of gas or mash the pedal down to try and get some speed the car bogs, stalls, and even wants to turn off some times.

Again, if I'm just cruising and take my time to let the car get up to highway speeds, it runs fine, but if I try to give it even a little bit of gas quickly the car bogs and takes a few seconds to respond.

I also have a problem with the car heating up to quickly. I know these cars run hot, but in my 5 years of ownership it didn't used to get this hot this quickly.

I changed the thermostat and flushed the coolant and burped the system as it says to in the manual, but that didn't help at all.

I haven't checked to see if there's any debree in the radiator so I still have to do that, but I just brought this problem up just incase they all have something to do with eachother.

I Ohm checked the injectors and they all were at about 12/13 ohms.

I used the paper clip method to pull up codes and this is what I got.

H74

4. H32
H55


I've used the search feature and have somewhat of an idea what it could be, but I'm not sure.

Any help is greatly appreciated!

 

Re the inability to put your foot down, it sounds like a fuel problem to me. Attach a pressure gauge, tape it to the windshield and go for a spin.

It's good advice to diagnose the problem, not throw money at it guessing. That said, if it was me I'd change the fuel filter regardless. Not much money and can't hurt - and could quite possibly solve your issue.

Let us know what you find!

 

I dont have a FSM in front of me but if i was to hazard to guess I would suggest still bad injectors. Even though they are ohming out they can still pulsate under load. Also replace the fuel filter(As its cheap) and check your fuel pressure at the rail.

As to the heating issue. Pull the radiator. I bet the front of it is full of bags, leaves, dirt, silt and debries which kills its cooling capabilities. A new OEM replacement is about $130. Just my thoughts, while you there change the hoses. Vaccumm out the shroud etc.

 

Appreciate the info fellas.

I had thought it could be the fuel pump from some of the info I've read on here. I have yet to check the fuel pressure as I do not have a guage.

I suspected it could of also been the injectors as well, but I would like to avoid buying new injectors at this time if that's not the problem. As mentioned above, I don't want to be throwing money at the car and not solving the problem.

I've changed the Fuel filter about 2 years back and the car has not been driven much since then, but I could change it again as it is inexpensive.

At the moment I'm thinking it's the fuel pump or possibly the EGR valve...

Code 32 has to do with an EGR failure? Is it possible that the EGR valve is bad and not the fuel pump?

Code 55 is engine running lean...I read that this occurs when there is something wrong with the fuel pump so that throws me off a little.

and Code 74 has something to do with the traction.

 

Your codes are EGR and engine lean. I would guess you have a bad fuel filter, pump and or fuel pressure regulator . Classic signs. Check your pressure. I would than go to bad injectors. The EGR I would probably disreguard for the moment.

 

Sorry for the slow update. I tested the Fuel pressure at the rail. The fuel pressure was at 38 at idle.

Took it out for a spin while I taped the fuel pressure gauge to my windshield, when I "Floored" the pedal the fuel pressure would drop to 22. When I'd just cruise it would go back to the mid 30's.

Any advice? I'm about to order some injectors soon from FIC, but wanted to know if my problem could be the fuel pump.

If so I'd order the fuel pump and a new fuel filter as well.

 

That sounds like low pressure at idle, and definitely low at increased throttle. Fuel pump is where I'd be spending my money, unless there's signs of a bad regulator, which will cause your oil to be diluted with gasoline.

 

Have not checked the oil. If it is diluted as you mentioned would I simply just change the regulator?

I plan on ordering an AC Delco fuel pump and fuel filter along with some injectors from FIC. The injectors are the original Multechs so they definetly need to be changed.

 

yes, if the oil is diluted with fuel, or there's fuel in the vacuum line on the regulator, the regulator is bad and needs replacement. Probably not the issue but worth checking.

 

22 psi is way too low at WOT. Try this....check the regulator as mentioned above....in fact, pinch off the return line with some vice grips and see if pressure comes up. If it does, your regulator is bad....if not.....

Pull the fuel pump assembly out and look for a leaking pulsator (rubber hose between fuel pump and pressure line). These get old and split sometimes, and leak fuel flow back into the tank. In fact, just replace it with a piece of FUEL INJECTION hose.

If you still have only 22 psi at WOT, it's time for a new fuel pump. The car will not run correctly with fuel pressure that low.

Glad to see you're troubleshooting and not just throwing parts and money at it.

 

Thanks fellas, definetly appreciated!

I will check the regulator as you stated.

I also forgot to mention that when I turned the car off, the fuel pressure when up to the high 40's and stayed like that for about 20 minutes till eventually I disconnected to the fuel gauge. Is that normal?

 

probably just shows the check valve in the pump assembly is functional.

 

Hey fellas, got an update for everyone.

I checked the vacuum line on the regulator and no fuel!


Last week I ordered a set of Bosch III's from FIC. I knew the culprit was most likely the fuel pump, but I've wanted to get rid of the original multechs for quite some time.

After installing the new injectors, I immediately noticed a difference in power. The car still bogged under acceleration, but there was a noticeable increase in power.

The car also started up alot quicker with the new injectors, something that was easily noticeable.

Finally I also installed a new AC Delco fuel pump and after driving her around today, wow!

Car not only starts quicker, but the bog under acceleration is gone!

After a 20 minute drive the car is running just as good as ever.

 

I love a happy ending!

 

life is good again